Field of the Invention
The present invention relates to a gear-changing apparatus. The apparatus preferably is for actuating a manual gearbox of a motorcycle having a drive engine, for carrying out a gear change with clutch engaged between the drive engine and the manual gearbox.
Background Art
In a motorcycle gearbox, gear changing usually proceeds such that the rider of the motorcycle interrupts the torque transmission between the drive engine and the manual gearbox by disengaging the clutch and then actuating the gear-change lever, which is coupled to the selector shaft, using his or her foot for changing up or changing down, and the rider then engaging the clutch again. The clutch typically is operated by pulling and releasing a clutch handle.
Although this procedure is still customary as before, gear-changing devices have also already become known which allow the gear changing of the manual gearbox with the clutch engaged. Such gear-changing devices are usually termed shifting assistance systems. These shifting assistance systems have the advantage that the time period during which the output torque provided by the drive engine for accelerating the motorcycle is interrupted can be reduced. The reduction in interruption time is advantageous in the case of sports motorcycles or racing motorcycles in particular. Gear changing without requiring the rider to actuate the clutch is also of interest for tour riding however, as the rider's clutch hand can be relieved as a result, particularly when riding for long distances; this contributes to relaxed and comfortable riding.
A motorcycle gear-change mechanism with a shifting assistance system for changing gear without actuating the clutch has become known on the basis of German Patent Publication DE 10 2012 209 963 A1. The shifting assistance system that has become known on the basis of this published document has a spring storage unit, which experiences a change in pre-stress due to the actuation of the gear-change lever. The change to a different gear is initiated and carried out by means of the energy stored in the spring. The shifting assistance system is placed concentrically onto the selector shaft of the gearbox in this case and protrudes laterally from the same.
A movement of the gear-change lever is transferred to the shifting assistance system in the process, and leads to a change of the spring pre-stress of the spring storage unit. Using the energy stored in the spring, the gear change process is then supported, wherein a sensor is provided on the housing of the shifting assistance system to detect the rider's desire to change gear, which determines the position of the gear-change lever, which is used in turn in a corresponding actuation by means of the rider for detecting the increased spring pre-stress of the spring storage unit of the shifting assistance system.
A gear-changing device for motorcycles has become known from German Patent Publication DE 10 2010 015 037 A1, which has a gear-change force transmission device, which is arranged between a gear-change lever of the motorcycle and a selector shaft of the gearbox. The force transmission device has two pressure springs, which are pre-stressed by means of a corresponding actuation of the gear-change lever during a gear-change process that is to be carried out. In this case, the two pressure springs have different spring characteristics, which means that the detection of the spring travel covered during the actuation of the gear-change lever in each case leads to different spring forces. The spring force generated in each case is monitored by an electronic device and evaluated to see if a gear-change force threshold has been reached, wherein the engine torque output by the drive engine is reduced and a gear-change process is carried out after the respective gear-change force threshold has been exceeded. Reaching the gear-change force threshold is therefore evaluated or interpreted as the rider's desire to change gear, whereupon the engine torque is reduced, in order to be able to carry out the actual gear change.
A gear-changing device very similar to the previously described gear-changing device has become known from German Patent Publication DE 10 2010 015 036 A1. Instead of operating with two pressure springs however, this device operates with only one pressure spring that is loaded in both gear-change directions. The rider's desire to change gear is determined in that the pre-stress force of the spring generated by means of the actuation of the gear-change lever is monitored for a gear-change force threshold; or, the spring travel covered by the spring for the actuation of the gear-change lever is detected by means of a sensor device and converted into a gear-change force threshold, which when exceeded is then interpreted as the rider's desire to change gear. If the gear-change force threshold is exceeded, the engine torque is reduced for carrying out the actual gear change process.
The aforementioned patent publications offer helpful background for the present invention. Accordingly, they are incorporated herein by reference in their entireties.
The commonality for all of the aforementioned gear-changing devices is that they have a spring in the force transmission path between the gear-change lever and the gearbox input, which spring is pre-stressed by a corresponding actuation of the gear-change lever by the rider of the motorcycle. The spring force thus generated by the rider when initiating a gear-change process is then evaluated as a signal for the short-term reduction of the engine torque after the exceedance of a corresponding threshold value, or else used as stored energy for carrying out the actual gear-change process.
Therefore, in all the above cases and commonly in the art, a spring device is located in the force transmission path between the gear-change lever and the gearbox input of the motorcycle gearbox, which spring device is actuated in such a manner when the gear-change lever is actuated, that it performs spring work; that is to say, the spring path of the spring present in the non-actuated position of the gear-change lever is subjected to a change. However, the presence of the spring device in the force-transmission path leads in all cases to a change of the gear-change behaviour perceived by the rider of the motorcycle, compared to a gear-change process in which a spring does not have to be pre-stressed in the force-transmission path first.
The spring leads to a gear-change behaviour that is perceived by the rider as indifferent or spongy. As a result, the spring makes it difficult for the rider to find neutral in particular, i.e., finding the neutral position for the motorcycle gearbox. The shifting assistance systems mentioned have a complex and therefore expensive structure, and are susceptible to faults. Spring fracture, for example, may occur at any time, whereupon the functioning of the shifting assistance system is no longer ensured and the vehicle equipped therewith can no longer be used until after a corresponding repair has been carried out. Furthermore, a spring is subject to signs of fatigue and set values, which change the gear-change behaviour of a shifting assistance system (provided with a spring) over a relatively long operating period, to which the rider must in turn adapt.
Shifting assistance systems also already have become known, which operate without a spring in the force transmission path between gear-change lever and selector shaft. These systems make use of a measurement of the force, using which the rider of the motorcycle actuates the gear-change lever. To trigger the gear-change process by influencing the engine torque, a set threshold value must be exceeded by the measured force value. If this threshold value is set to be high, the rider must actuate the gear-change lever with a high force, so that they can change gear, which has a tiring effect on the rider, if the threshold value is set to be low, even a brief inadvertent touch of the gear-change lever by the rider causes the threshold value to be exceeded and therefore an undesired gear-change process, which constitutes an unpleasant surprise for the rider. Shifting assistance systems of this type, which usually operate using load cells or strain gauges, are typically offered by Translogic Systems Ltd., for example. This description makes it clear that the rider must in turn adapt to the triggering behaviour of the shifting assistance system.
On this basis, it is the object of the present invention to create a gear-changing device for changing gear without actuating the clutch on a motorcycle, which makes it possible for a rider to use the motorcycle without the rider's having to adapt to a changed gear-changing behaviour. To achieve this object, the invention has the features specified in claim 1. Advantageous embodiments are disclosed in the further claims.